Method of making coated articles and coated articles made thereby

Abstract

A method of making a coated substrate includes providing a substrate having a functional coating with a first emissivity value; depositing a coating material having a second emissivity value over at least a portion of the functional coating prior to heating to provide a coating stack having an emissivity value greater than the emissivity value of the functional coating; and heating the coated substrate.

1. A method of making a coated substrate, comprising:
 providing a substrate having a functional coating including one or more infrared reflective films comprising a reflective metal with a first emissivity value; and  
 depositing a coating material comprised of 35 wt. % to 100 wt. % alumina and 0 wt. % to 65 wt. % silica having a second emissivity value over at least a portion of the functional coating to provide a coating stack having an emissivity value greater than the emissivity value of the functional coating.  
 
     
     
       2. The method of  claim 1 , including heating the coated substrate. 
     
     
       3. The method of  claim 1 , wherein the coating material comprises 75 wt. % to 85 wt. % alumina and 15 wt. % to 25 wt. % silica. 
     
     
       4. The method of  claim 1 , wherein the coating material comprises 86 wt. % to 90 wt. % alumina and 10 wt. % to 14 wt. % silica. 
     
     
       5. The method of  claim 1 , including depositing the coating material to a thickness in the range of 100 Å to 1.5 microns. 
     
     
       6. The method of  claim 1 , wherein the coating material has an index of refraction substantially the same as the index of refraction of the substrate. 
     
     
       7. The method of  claim 1 , wherein the substrate is glass and the method includes depositing the coating material to have a thickness in the range of 100 Å to 1.5 microns and a refractive index of 1.5±0.2. 
     
     
       8. The method of  claim 1 , wherein the first emissivity value is different than the second emissivity value. 
     
     
       9. A method of making a coated substrate, comprising:
 providing a substrate having a functional coating with a first emissivity value; and  
 depositing a coating material comprised of 75 wt. % to 85 wt. % alumina and 15 wt. % to 25 wt. % silica having a second emissivity value over at least a portion of the functional coating to provide a coating stack having an emissivity value greater than the emissivity value of the functional coating.  
 
     
     
       10. A method of making a coated substrate, comprising:
 providing a substrate having a functional coating with a first emissivity value; and  
 depositing a coating material comprised of 86 wt. % to 90 wt. % alumina and 10 wt. % to 14 wt. % silica having a second emissivity value over at least a portion of the functional coating to provide a coating stack having an emissivity value greater than the emissivity value of the functional coating.